Ynet adds "Inside the haredi
community there were calls from rabbis ... to attend the rally,
and the community's leaders gave a rare permission for women to attend –
but on separate streets. All boys from the ages of nine and older were
also called to attend."

It probably has never happened since the Israelites gathered at Mt. Sinai to receive the Ten Commandments and probably will not happen again today, but the Talmud says that a special blessing should be recited when one sees 600,000 Jews gathered together in one place:

ברוך אתה ה' אלהינו מלך העולם חכם הרזים

Blessed are you, O Lord our God, ruler of the universe,
the wise One who knows all secrets.

(Rashi interprets this to mean that that only Hashem knows the secrets that each of these individual people think.)

Meanwhile 4,500 (some say 3,500) police and "ushers" are assigned to try to keep order in today's huge gathering.
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Times of Israel is having a live blog to update us as it happens.
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Either conscription has to be ended for all citizens or all citizens have to obey the state's laws. You cannot have a select few who avoid conscription, choose not to pay taxes, drive dangerously on the roads or evade any other state law.

When I was 17-18 years old, together with some girlfriends we got lost in Jerusalem, and came to an area where orthodox jews were living. Some of the men were throwing stones at us! We got scared and ran away..... We did not do anything..... and could not see or read any signs saying that tourists were not allowed walking there.

Jerusalem is a fantastic city. And we had plenty of good memories from the city too. We just got so scared..... and have never been back. Of course I know people who have had great holidays there.

Gunn, I'm sorry about that incident. Probably you girls had a tiny bit of skin not covered. But throwing stones is really over-reacting and terrible. Even the police is afraid to go into some of the extreme ultra Orthodox neighborhoods. There are a few signs asking people not to come in in groups and demanding strict modest dress codes.